Re: [PATCH] staging: media: atomisp: Use kmap_local_page() in hmm_set()

[Ira Weiny]

On Wed, Apr 13, 2022 at 11:22:10PM +0200, Fabio M. De Francesco wrote:
> The use of kmap() is being deprecated in favor of kmap_local_page()
> where it is feasible. In file pci/hmm/hmm.c, function hmm_set() calls
> kmap() / kunmap() where kmap_local_page() can instead do the mapping.
> 
> With kmap_local_page(), the mapping is per thread, CPU local and not
> globally visible. Therefore, hmm_set()() is a function where the use
> of kmap_local_page() in place of kmap() is correctly suited.
> 
> Convert the calls of kmap() / kunmap() to kmap_local_page() /
> kunmap_local().
> 
> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>

Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>

> ---
>  drivers/staging/media/atomisp/pci/hmm/hmm.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/media/atomisp/pci/hmm/hmm.c b/drivers/staging/media/atomisp/pci/hmm/hmm.c
> index 6394385b6637..46ac082cd3f1 100644
> --- a/drivers/staging/media/atomisp/pci/hmm/hmm.c
> +++ b/drivers/staging/media/atomisp/pci/hmm/hmm.c
> @@ -563,7 +563,7 @@ int hmm_set(ia_css_ptr virt, int c, unsigned int bytes)
>  		idx = (virt - bo->start) >> PAGE_SHIFT;
>  		offset = (virt - bo->start) - (idx << PAGE_SHIFT);
>  
> -		des = (char *)kmap(bo->page_obj[idx].page) + offset;
> +		des = (char *)kmap_local_page(bo->page_obj[idx].page) + offset;
>  
>  		if ((bytes + offset) >= PAGE_SIZE) {
>  			len = PAGE_SIZE - offset;
> @@ -579,7 +579,7 @@ int hmm_set(ia_css_ptr virt, int c, unsigned int bytes)
>  
>  		clflush_cache_range(des, len);
>  
> -		kunmap(bo->page_obj[idx].page);
> +		kunmap_local(des);
>  	}
>  
>  	return 0;
> -- 
> 2.34.1
>